Conventionally, users install software, for example, from a CD-ROM or like storage medium or over the Internet, (hereinafter, “original software” which is a type of content) on their computers (communication terminals). Thereafter, every time the user needs a software update, he obtains a patch or updater (updater software) from, for example, the original software distributor's home page, over a network to correct the original software.
To facilitate the action, systems exist which automatically deliver updater software information to the communication terminal from the software provider's server machine over the network. Technology related to the system is disclosed in, for example, Japanese unexamined patent application 11-272471 (Tokukaihei 11-272471/1999; published on Oct. 8, 1999), Japanese unexamined patent application 11-312080 (Tokukaihei 11-312080/1999; published on Nov. 9, 1999), and Japanese unexamined patent application 7-129407 (Tokukaihei 7-129407/1995; published on May 19, 1995).
Tokukaihei 11-272471/1999 discloses a remote software installation technique where software is distributed to multiple computers interconnected via a network. Specifically, when the transmitting computer delivers software used on receiving computers, the transmitting computer records version information of each piece of delivered software for each receiving computer. Before delivering a new version of the software, the transmitting computer compares that version to the version of software already delivered to each receiving computer. The new version of software is thus delivered only to receiving computers with older versions.
Tokukaihei 11-312080/1999 discloses a technique where a program server machine broadcasts program update information over a network, and a client terminal device determines whether the program needs an update based on received program update information so that only those updates which are determined to be necessary are performed.
In Tokukaihei 7-129407/1995, a server transfers system version information to client terminals so that the client terminals can determine whether they have a program whose version matches that indicated in the information. If the versions do not match, the client terminal decides whether to update the program. Depending on this decision, an update is performed by the server transferring the latest version of the program to the client terminal for storage in the client terminal's program database. Tokukaihei 7-129407/1995 discloses the following modes of updating: (1) All programs are updated. (2) Only old versions of programs are updated according to the version information of the client terminal. (3) Only those selected by the user are updated.
Some trouble may in the communication terminal cause a malfunction of an updated version of software which was updated using an updater, requiring reinstallation of the original software. The user will desire to restore the software condition to the point at which a last updater was installed. The foregoing conventional technology, however, is not capable of responding the desire due to the following problems.
According to the technology disclosed in Tokukaihei 11-272471/1999, the latest version of the software is delivered when the original software is reinstalled in the computer on the receiving end. However, the version information stored in the transmitting computer does not reflect the fact that the original software has been reinstalled in the receiving computer which is thus currently running the original version. Updates older than the latest one are not automatically carried out.
According to the technology disclosed in Tokukaihei 11-312080/1999, only those programs in relation to which update information is broadcast are updated through version comparison. If the user wants to obtain other programs, he must identify the updaters delivered up to that moment to request the server to deliver the identified updaters. The user needs to make notes of the titles of the delivered updaters.
Mode 1 of update operation disclosed in Tokukaihei 7-129407/1995 updates all programs. The user cannot chose which programs are to be updated or not to be updated. He cannot recover the pre-installation configuration because some updated programs may never have been delivered to, and wanted by, the user.
Mode 2 selects only later versions of a program than indicated in the date and time information about the update(s) of the program in the client terminal. If the original software is reinstalled in the client terminal, only those programs newer than the update date and time are selected, and those programs older than the update date and time are not selected.
Mode 3 allows the user no other choice but to repeat the same updating procedures as he once did, starting with the reinstallation of the original software. He then must identify and obtain the same patches and other updaters again as the previous ones, so as to recover the pre-reinstallation configuration.